Energy density means getting more for your calories
Energy density is the number of calories (energy) in a given amount (volume) of food. By choosing foods that are low in calories, but high in volume, you can eat more and feel fuller on fewer calories. Fruits and vegetables are good choices because they tend to be low in energy density and high in volume.
So what about raisins? They're actually high in energy density — they pack a lot of calories into a small package. For example, 1/4 cup of raisins has about 100 calories. For about the same number of calories you could have 1 cup of grapes — and get more bite for your calorie buck.
High versus low energy density
Foods high in energy density include fatty foods, such as many fast foods, and foods high in sugar, such as sodas and candies. For example, a small order of fast-food fries has more than 200 calories.
For the same calories, you could have a heaping helping of fresh fruits and vegetables — such as this salad made with 10 cups of spinach, 1 1/2 cups of strawberries and a small apple. Plus with fresh fruits and vegetables, you get a plethora of valuable nutrients — not just empty calories. These foods also take longer to eat and are filling, which helps curb your hunger.
A lunch that will keep you going
Tempted to grab a candy bar for lunch? For the same calories, you could choose a healthier and more filling option, such as pita stuffed with low-fat chicken salad.
Pick a snack that packs a punch
Energy density is also important when you're snacking. If you're working on weight loss or maintenance, you want to keep your snacks at about 100 calories. One ounce of potato chips is about 150 calories. Or for only 100 calories, you could snack on 3 1/2 cups of air-popped popcorn.